Brush for small motors and dynamos



Jan. 10, 1928.

R. H. WAPPLER BRUSH FOR SMALL MOTORS AND nymmos Filed May 27. 1924 JEL'IREl INVENTOR fizz/M1010 H WAPPL-ER Muzak/4 14% ATTORNEY Patented Jan. 19, 1928.

UNITED STATES PATENT OFFICE.

BEINHOLD H. WAPPLER, CF YONKERS, NEW YORK, ASSIGNOR TO WAPPLER ELECTRIC COMPANY, INC, A CORPORATION OF NEW YORK.

BRUSH FOR SMALL MOTORS AND DYNAMOS.

Application filed May 27,

My invention relates to Contact brushes for small motors and dynamos, my more par ticular purpose being to g re the contact brushessuch construction and arrangement as to render them etiicient and reliable in action under conditions which would or dinarily prevent contact brushes from o1erating satisfactorily, if at all.

Stating the problem more specifically, 1

1o seek to produce a contact brush of very simple form and well adapted for use upon motors-and dynamosof unusually small size and low power; such, for instance as will run on av mere fraction of a watt, and which can be operated at potentials far lower than are generally employed in connection with small motors and dynam I also seek to give my contact brushes such form as to enable them to maintain good contact continuously with the commutator even if these parts he used with oil, Vaseline. or other lubricant, and without interfering with the flow of the delicate electric currents here contemplated.

In addition I seek to render the contact brushes self-adjusting relatively to the commutator with which they are used, and by so doing I seek to facilitate the use of these parts by persons having little or no special :10 training for this purpose, the form and ar rangement of the parts being such that any displacement of the contact brush, accidental or otherwise, may be corrected quickly and without the necessity for any extreme ae- 22.3 curacy in adjustment.

Reference is made to the accompanying drawing forming a part of this specification, and in which like reference characters indicate like parts throughout all of the figures.

Figure l is a plan view of a small electric motor equipped with a pair of my improved contact brushes and a commutator adapted for use therewith, certain portion-s of the mechanism being brohen away.

Figure 2 is a section on the line 22 of Figure 1, looking in the direction indicated by the arrows.

Figure 3 is a section on the line 3-43 of Figure 1 and showing the commutator and contact brushes, certain other parts being omitted. I

Figure 4C is a. vertical section through the commutator and Contact brushes, and is taken on the line fof Figure 3.

Figure 5 is a View partly in side elevation 1924. Serial No. 716,114.

andpartly in section, showing a form of my improved brush dil'fering slightly from the one appearing. in Figures 1, 3 and 41.

A base plate is shown at 5, and is provided with a lug 6 integral with it and extending to the left according to Figure 2.

Resting upon the base plate?) and engagthe lug 6 is a permanent magnet 7. ihis magnet is held in position by a bolt 8, which engages the lug 6 and extends upwardly through holes in this lug and in the permanent magnet- 7. The bolt 8 carries revolubly mounted upon its upper end two nuts 9 and 10, the nut 10 serving as a lock for the nut 9.

Between the poles 11 and 12 of the magnet 7 is located an armature 13, mounted rigidly upon a revoluble shaft 1 1. and. provided with windings 15.

The shaft 14: is mounted in bearings 16 and 17, and carries a worm 18, engaging a worm wheel 19, the latter being mounted upon a shaft- 20, driven by rotation of the worm wheel.

he shaft 1& is furtherprovided with a gear pinion 21. Both this gear pinion and the shaft 20, or either of them, can be used for actuating any light mechanism suit-able to be driven by a motor of this type. However, the gear members 18, 19, 20 and 21. just described are not essential to my invention, as the rotation of the shaft 141 can be utilized in any other way.

The reason for using a permanent magnet 7 instead of an electro-magnet is merely to save the energy required to energize the magnet.

Connected with the windings are leads 22, these leads being also connected with commutator sectors 23, carried by the shaft- 14 and insulated therefrom and from each other, as indicated more particularly in Figures 3 and etc The three commutator sectors 28 collectively constitute a con'm'uitator, the latter being insulated-from the shaft l& by means of a sleeve 21 of insulating material, held in position by two collars 25 of metal. The commutator is insulated from these collars by two rings 26 of insulating material.

The commutator is provided with a groove 27, extending peripherally around it and having in cross section a semi-circular form, as may be understood from Figure 4;.

Located upon opposite sides of the com- Ill and for a. very small motor or dynamo ma through sleeves'3O of insulating material,

into which they are threaded. Each sleeve is provided with an annular head 31, so

that by turning thenutsl relatively to the bolts 29,'the bolts 31 may be forced tightly against the adjacent annular heads 81 of the tubular. sleeves 30. The two sleeves 30 extendthrough holes in a metallic stand-,

ard 33, and are held firmly in position by screws 34: carried by this standard, as may be understood from Figure 3. The standard 33 is held in position upon the base plate 5 by a screw 35. Two conductors 36, 37, are connected with the bolts 29 by means of the nuts 32. Each bolt 29, with the sleeve 30 upon which it is mounted, and the nut 32 carried by the bolt, thus serves as a binding post.

Each contact brush 28 is made of metal, preferably phosphor bronze or hard copper. However, the'brushes may be made of other metals asoccasion may require. The wire of the brush may be as coarse as required,

be assmall as No. 30 Brown and Sharpe gage, or possibly even smaller and the external dlameterot the brush need not exceed onetwentieth of an inch.

Each brush 28 is simply a single piece of hard drawn, th1n wire, celled into the form of a spiral spring, the convolutions being,

close together and the spiral as a whole having the proximate form of a cylinder.

In some instances I use two coil springs 36 and 37 as shown in Figure 5, in the con struction of the brush.

Each brush presses gently against the commutator at practically a single point of contact. The pressure of the brush against the commutator is very gentle, so that its friction is negligible in practice, and yet the engagement between the brush and the 'comnmtator is about as nearly perfect as could reasonably be expected. its own tension self-centered within the 'com mutator 27. Because of the refinement of the engagement of the brushes with the commutator, the current flowing through the machine is always uniform.

Owing to the closeness of the fit between the commutator and the contact brushes, and the comparative freedom from friction at the pointsofcontact, it is not always strictly necessary to employ lubricant at these 7 greater power The brush is. by

parts. However, lubricants can readily be used, and in many instances to considerable advantage. For this purpose a thin oil is preferable, but thicker oils or even Vaseline can be employed, without danger of umming the parts or even interfering with the free passage of the current through the commutator and brushes. Y

I have demonstrated repeatedly in actual practice that lubrication with oil or Vaseline does not impair the flow of the current, even when the structural parts are exceedingly small. In the particular instance here demonstrated the motor is of very small size and employs from atenth to a quarterof an ampere, and a potential of one and a halt volts. This motor runs verv steadily on a power of half a watt, or even less. In in stances where there are appreciable quantities of dust or grease on the commutator and-brushes of the kind here contemplated, this does not generally interfere with the work of the motor.

In this connection it should be borne in mind that a motor running on a small fraction of an ampere and at a low potential, say one or two volts, it is ordinarily a difficult matter to use oil, Vaseline, grease of any kind, or in fact any sort of lubricant, without interfering seriously with the flow of the currents.

I have experimented extensively along this line, and have tried many forms of contact brushes; but brushes of the kind above described, and shown in the accompanying drawing, are oi' the only kind I have yet found capable of working, with any degree of satisfaction, under the unusually severe conditions required by a motor of very small size and low power as above contemplated.

My improved brushes admit of cheapness in manufacture, and are Well adapted for quantity production and for. standardization. They can be made of largesize and thus adapted tormotors and dynamos for than the one described, though their special province appears to be in connection with motors and dynamos of exceedingly small power.

, I do not limit myself to the precisemechanism shown, as variations may be made therein without departing from my invention, the scope i i with my claims.

Having thus described my invention what I claim as new and desire to secure by Let: ters Patent is as follows:

1. A device'ot' the character described comprising a revoluble commutator provided with an annular groove semi-circular in cross-section, a standard disposed adjacent of which is commensurate helix and having in cross section the proximate form of a cylinder fitting into said annular groove and each being made of a single piece of wire.

2. A device of the character described comprising a commutator provided with an annular groove, a pair of spring brushes engaging said commutator and extending tangentially to the bottom of the said groove,

each brush consisting of a Wire coiled helil0 cally and as thus coiled fitting into groove, and means for supporting spring brushes.

Signed at New York, in the county of said New York and State of New York, this 23rd day of May, 192%.

REIN HOLD H. XVAPPLER.

said 

